One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10,13,18)(11,19,22,15)(12,16,14,17)(20,24,21,23)(25,26,29,32)(27,30,35,39)(28,31,37,33)(34,38,36,40)(2,5)(6,8)(9,11,13,22)(10,15,18,19)(12,21,14,20)(16,24,17,23)(25,27,29,35)(26,30,32,39)(28,36,37,34)(31,40,33,38)(1,3)(2,6)(4,7)(5,8)(10,16)(11,20)(12,14)(17,18)(21,22)(23,24)(26,31)(28,37)(30,38)(32,33)(34,36)(39,40) involution — undirected(3,7)(6,8)(9,12,13,14)(10,17,18,16)(11,21,22,20)(15,23,19,24)(26,32)(30,39)(31,33)(38,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.